mirror of
https://github.com/moses-smt/mosesdecoder.git
synced 2024-09-11 11:25:40 +03:00
107 lines
3.5 KiB
C++
107 lines
3.5 KiB
C++
#include "search/nbest.hh"
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#include "util/pool.hh"
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#include "moses/Util.h"
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#include <algorithm>
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#include <functional>
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#include <queue>
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#include <cassert>
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#include <cmath>
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namespace search {
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NBestList::NBestList(std::vector<PartialEdge> &partials, util::Pool &entry_pool, std::size_t keep) {
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assert(!partials.empty());
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std::vector<PartialEdge>::iterator end;
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if (partials.size() > keep) {
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end = partials.begin() + keep;
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NTH_ELEMENT4(partials.begin(), end, partials.end(), std::greater<PartialEdge>());
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} else {
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end = partials.end();
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}
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for (std::vector<PartialEdge>::const_iterator i(partials.begin()); i != end; ++i) {
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queue_.push(QueueEntry(entry_pool.Allocate(QueueEntry::Size(i->GetArity())), *i));
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}
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}
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Score NBestList::TopAfterConstructor() const {
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assert(revealed_.empty());
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return queue_.top().GetScore();
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}
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const std::vector<Applied> &NBestList::Extract(util::Pool &pool, std::size_t n) {
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while (revealed_.size() < n && !queue_.empty()) {
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MoveTop(pool);
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}
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return revealed_;
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}
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Score NBestList::Visit(util::Pool &pool, std::size_t index) {
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if (index + 1 < revealed_.size())
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return revealed_[index + 1].GetScore() - revealed_[index].GetScore();
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if (queue_.empty())
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return -INFINITY;
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if (index + 1 == revealed_.size())
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return queue_.top().GetScore() - revealed_[index].GetScore();
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assert(index == revealed_.size());
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MoveTop(pool);
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if (queue_.empty()) return -INFINITY;
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return queue_.top().GetScore() - revealed_[index].GetScore();
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}
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Applied NBestList::Get(util::Pool &pool, std::size_t index) {
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assert(index <= revealed_.size());
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if (index == revealed_.size()) MoveTop(pool);
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return revealed_[index];
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}
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void NBestList::MoveTop(util::Pool &pool) {
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assert(!queue_.empty());
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QueueEntry entry(queue_.top());
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queue_.pop();
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RevealedRef *const children_begin = entry.Children();
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RevealedRef *const children_end = children_begin + entry.GetArity();
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Score basis = entry.GetScore();
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for (RevealedRef *child = children_begin; child != children_end; ++child) {
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Score change = child->in_->Visit(pool, child->index_);
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if (change != -INFINITY) {
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assert(change < 0.001);
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QueueEntry new_entry(pool.Allocate(QueueEntry::Size(entry.GetArity())), basis + change, entry.GetArity(), entry.GetNote(), entry.GetRange());
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std::copy(children_begin, child, new_entry.Children());
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RevealedRef *update = new_entry.Children() + (child - children_begin);
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update->in_ = child->in_;
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update->index_ = child->index_ + 1;
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std::copy(child + 1, children_end, update + 1);
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queue_.push(new_entry);
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}
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// Gesmundo, A. and Henderson, J. Faster Cube Pruning, IWSLT 2010.
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if (child->index_) break;
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}
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// Convert QueueEntry to Applied. This leaves some unused memory.
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void *overwrite = entry.Children();
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for (unsigned int i = 0; i < entry.GetArity(); ++i) {
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RevealedRef from(*(static_cast<const RevealedRef*>(overwrite) + i));
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*(static_cast<Applied*>(overwrite) + i) = from.in_->Get(pool, from.index_);
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}
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revealed_.push_back(Applied(entry.Base()));
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}
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NBestComplete NBest::Complete(std::vector<PartialEdge> &partials) {
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assert(!partials.empty());
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NBestList *list = list_pool_.construct(partials, entry_pool_, config_.keep);
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return NBestComplete(
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list,
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partials.front().CompletedState(), // All partials have the same state
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list->TopAfterConstructor());
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}
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const std::vector<Applied> &NBest::Extract(History history) {
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return static_cast<NBestList*>(history)->Extract(entry_pool_, config_.size);
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}
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} // namespace search
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